Tracy arrived in Moscow earlier this week. Russian Foreign Ministry spokeswoman Maria Zakharova said on Friday that the new U.S. ambassador would not improve ties between the two countries because of what she called Washington's ongoing "hybrid war" against Russia.

Relations between Washington and Moscow have been at rock bottom since Russia's invasion of Ukraine last February. Russia casts the war as confronting what is says is an aggressive and expansionist U.S.-led NATO alliance, while Kyiv and its allies call Russia's actions an unprovoked land grab.

According to Ryabkov, the traditional presentation of copies of credential by Tracy is already agreed upon.

"It will take place literally at the beginning of the week. It is expected that the transfer of copies of credentials by Ambassador Tracy will be made to me," he said.

(Reporting by Reuters; Editing by Frances Kerry)